TY - JOUR A1 - Kugler, Felix A1 - Aumüller, Jessica A1 - Krcmar, Wolfgang A1 - Teipel, Ulrich T1 - Construction and Demolition Residuals as Raw Materials for the Production of Novel Geopolymer Building Materials JF - Crystals N2 - The increasing number of new construction projects requiring high-quality building products, which, in turn, emit enormous amounts of CO2, runs counter to European and global climate goals. The increasing occupation of valuable landfill space is also an ecological problem. To meet these challenges without having to lower living standards, more ecological building materials should be used in the future. Geopolymers or alkali-activated materials, which, unlike conventional building materials, can be produced and used without a prior burning or calcination process, offer a comparatively low-CO2 alternative. Significant CO2 emissions can already be saved by using this technology. The aim of this work is to investigate whether geopolymers can also be produced from construction and demolition residuals generated by the construction industry in order to counteract the problem of the increasing use of landfill space and, at the same time, to further reduce greenhouse gas emissions in the production of building materials. For this purpose, various residual materials from the construction and demolition industry are investigated by means of XRF, XRD, and IR spectroscopy for their setting behavior by alkaline activation. At the same time, the characteristic values of compressive strength, flexural strength, bulk density, and thermal conductivity, which are important for building materials, are determined in order to test the possible applications of the resulting materials as building materials. Y1 - 2022 U6 - https://doi.org/10.3390/cryst12050678 SN - 2073-4352 VL - 12 IS - 5 PB - MDPI AG ER - TY - JOUR A1 - Kugler, Felix A1 - Fehn, Thomas A1 - Sandner, Maximilian A1 - Krcmar, Wolfgang A1 - Teipel, Ulrich T1 - Microstructural and mechanical properties of geopolymers based on brick scrap and fly ash JF - International Journal of Ceramic Engineering & Science N2 - In the present work, the influence of increasing brick scrap additions on the setting behavior and material properties of fly ash‐based geopolymers is investigated. The geopolymers produced are tested for their compressive strengths, bulk densities, and thermal conductivities, among other properties. Both the starting materials and the produced geopolymers are also investigated by infrared spectroscopy, X‐ray diffraction analysis, and scanning electron microscopy to show the relationship between the solidification behavior and the resulting material properties. The investigations show that brick scrap is very suitable as a matrix material for geopolymer production. Increasing brick scrap additions lead, among other things, to a reduction in bulk density, thermal conductivity and compressive strength. KW - geopolymers KW - mechanical properties KW - microstructure KW - waste disposal Y1 - 2022 U6 - https://doi.org/10.1002/ces2.10120 SN - 2578-3270 VL - 4 IS - 2 SP - 92 EP - 101 PB - Wiley ER - TY - JOUR A1 - Kugler, Felix A1 - Karrer, Jörg A1 - Krcmar, Wolfgang A1 - Teipel, Ulrich T1 - Setting behavior and mechanical properties of concrete rubble fly ash geopolymers JF - Open Ceramics N2 - Due to concerns about the very high primary raw material consumption and CO2 emissions of the economically important construction sector, the demand for “green” binders is growing. One option that is receiving particular attention is the material class of “geopolymers”, which could be used as a substitute for Portland cement. This new group of binders not only exhibits improved mechanical properties, but is also characterized by particularly low carbon dioxide emissions in the course of its production. This work focuses on the influence of concrete rubble on the setting behavior and microstructural properties of fly ash-based geopolymers. In the course of the investigations, the manufactured geopolymer samples are examined for the material parameters relevant to building materials, namely compressive strength, raw density and thermal conductivity. The setting behavior and the forming structures are investigated by infrared spectroscopy, X-ray diffraction analysis and scanning electron microscopy. The present work is intended to contribute to the development of a suitable recycling strategy for the material recycling of concrete rubble in novel substitute construction materials, the geopolymers. KW - Geopolymer KW - Binder KW - Concrete rubble KW - Building material KW - Circular economy KW - CO2-Reduction Y1 - 2022 U6 - https://doi.org/10.1016/j.oceram.2022.100286 SN - 2666-5395 VL - 11 PB - Elsevier BV ER - TY - JOUR A1 - Fehn, Thomas A1 - Kugler, Felix A1 - Tübke, Beatrice A1 - Schweppe, Rainer A1 - Mebert, Phillip A1 - Krcmar, Wolfgang A1 - Teipel, Ulrich T1 - Charakterisierung und Störstoffanalyse von rückgewonnenen Stoffströmen aus Wärmedämmverbundsystemen JF - Chemie Ingenieur Technik N2 - Aufgrund steigender energetischer Anforderungen ist der Anteil an verbauten Wärmedämmverbundsystemen (WDVS) in den vergangenen 50 Jahren deutlich gestiegen. Trotz der Langlebigkeit dieser Systeme fallen zunehmend WDVS‐Abfälle an, deren Nutzungsphase beendet ist. Aufgrund der komplexen Bauweise sowie einer Vielzahl an unterschiedlich verbauten Materialien der vergangenen Generationen bestehen viele Unsicherheiten und Probleme bei der sortenreinen und schadstoffarmen Aufbereitung solcher Systeme. Im Rahmen der vorliegenden Arbeit wurde ein Aufbereitungsverfahren für WDVS entwickelt. Damit gelingt eine weitestgehende Rückgewinnung verwertbarer Werkstofffraktionen. Diese wurden auf etwaige Stör‐ und Schadstoffe wie Flammschutzmittel sowie auf deren Reinheit untersucht. Y1 - 2021 U6 - https://doi.org/10.1002/cite.202000215 SN - 0009-286X VL - 93 IS - 5 SP - 771 EP - 780 PB - Wiley ER -